At the moment you can't tag a design when you upload, not even once.
I don't believe there is a way. It would be nice however.
Sure ther is. If you look at the upper left under the "Answers" tab it shows 3 sortable categories. If a 4th were added - like the name of the designer, that would help. That would let you sort through each person instead of all the entries that shuffle each minute/hour/day because of comments and flowers.
:-)